[PATCH 1/1] mktree: long is bigger on 64-bit

[PATCH 1/1] mktree: long is bigger on 64-bit

[Serge E. Hallyn]

mktree's hash function assumes that long is 32 bits.  Fix.

Signed-off-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 mktree.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/mktree.c b/mktree.c
index 7a8cecc..0195974 100644
--- a/mktree.c
+++ b/mktree.c
@@ -724,6 +724,7 @@ static int ckpt_make_tree(struct ckpt_ctx *ctx, struct task *task)
 	struct task *child;
 	struct pid_swap swap;
 	pid_t newpid;
+	int status;
 	int ret;
 
 	ckpt_dbg("pid %d: pid %d sid %d parent %d\n",
@@ -765,7 +766,7 @@ static int ckpt_make_tree(struct ckpt_ctx *ctx, struct task *task)
 	/* 3rd pass: bring out your deads ... */
 	for (child = task->children; child; child = child->next_sib) {
 		if (child->flags & TASK_DEAD) {
-			ret = waitpid(child->rpid, NULL, 0);
+			ret = waitpid(child->rpid, &status, 0);
 			if (ret < 0) {
 				perror("waitpid");
 				return -1;
@@ -1291,7 +1292,8 @@ static void hash_exit(struct ckpt_ctx *ctx)
 static inline int hash_func(long key)
 {
 	unsigned long hash = key * GOLDEN_RATIO_PRIME_32;
-	return (hash >> (32 - HASH_BITS));
+	//return (hash >> (32 - HASH_BITS));
+	return (hash >> (sizeof(long)*8 - HASH_BITS));
 }
 
 static int hash_insert(struct ckpt_ctx *ctx, long key, void *data)
-- 
1.6.1.1

Re: [PATCH 1/1] mktree: long is bigger on 64-bit

[Matt Helsley]

On Tue, May 12, 2009 at 10:08:30PM -0500, Serge E. Hallyn wrote:
> mktree's hash function assumes that long is 32 bits.  Fix.
> 
> Signed-off-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> ---
>  mktree.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/mktree.c b/mktree.c
> index 7a8cecc..0195974 100644
> --- a/mktree.c
> +++ b/mktree.c
> @@ -724,6 +724,7 @@ static int ckpt_make_tree(struct ckpt_ctx *ctx, struct task *task)
>  	struct task *child;
>  	struct pid_swap swap;
>  	pid_t newpid;
> +	int status;
>  	int ret;
> 
>  	ckpt_dbg("pid %d: pid %d sid %d parent %d\n",
> @@ -765,7 +766,7 @@ static int ckpt_make_tree(struct ckpt_ctx *ctx, struct task *task)
>  	/* 3rd pass: bring out your deads ... */
>  	for (child = task->children; child; child = child->next_sib) {
>  		if (child->flags & TASK_DEAD) {
> -			ret = waitpid(child->rpid, NULL, 0);
> +			ret = waitpid(child->rpid, &status, 0);
>  			if (ret < 0) {
>  				perror("waitpid");
>  				return -1;
> @@ -1291,7 +1292,8 @@ static void hash_exit(struct ckpt_ctx *ctx)
>  static inline int hash_func(long key)
>  {
>  	unsigned long hash = key * GOLDEN_RATIO_PRIME_32;
> -	return (hash >> (32 - HASH_BITS));
> +	//return (hash >> (32 - HASH_BITS));
> +	return (hash >> (sizeof(long)*8 - HASH_BITS));

I'm guessing the // comment isn't intentional. Also, how about using sizeof(key)
instead of manually inserting its type?

Cheers,
	-Matt Helsley

Re: [PATCH 1/1] mktree: long is bigger on 64-bit

[Serge E. Hallyn]

Quoting Matt Helsley (matthltc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
> On Tue, May 12, 2009 at 10:08:30PM -0500, Serge E. Hallyn wrote:
> > mktree's hash function assumes that long is 32 bits.  Fix.
> > 
> > Signed-off-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> > ---
> >  mktree.c |    6 ++++--
> >  1 files changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/mktree.c b/mktree.c
> > index 7a8cecc..0195974 100644
> > --- a/mktree.c
> > +++ b/mktree.c
> > @@ -724,6 +724,7 @@ static int ckpt_make_tree(struct ckpt_ctx *ctx, struct task *task)
> >  	struct task *child;
> >  	struct pid_swap swap;
> >  	pid_t newpid;
> > +	int status;
> >  	int ret;
> > 
> >  	ckpt_dbg("pid %d: pid %d sid %d parent %d\n",
> > @@ -765,7 +766,7 @@ static int ckpt_make_tree(struct ckpt_ctx *ctx, struct task *task)
> >  	/* 3rd pass: bring out your deads ... */
> >  	for (child = task->children; child; child = child->next_sib) {
> >  		if (child->flags & TASK_DEAD) {
> > -			ret = waitpid(child->rpid, NULL, 0);
> > +			ret = waitpid(child->rpid, &status, 0);
> >  			if (ret < 0) {
> >  				perror("waitpid");
> >  				return -1;
> > @@ -1291,7 +1292,8 @@ static void hash_exit(struct ckpt_ctx *ctx)
> >  static inline int hash_func(long key)
> >  {
> >  	unsigned long hash = key * GOLDEN_RATIO_PRIME_32;
> > -	return (hash >> (32 - HASH_BITS));
> > +	//return (hash >> (32 - HASH_BITS));
> > +	return (hash >> (sizeof(long)*8 - HASH_BITS));
> 
> I'm guessing the // comment isn't intentional. Also, how about using sizeof(key)
> instead of manually inserting its type?

Uh, yeah, the other two hunks weren't intentional either.  Crappy patch.
But it still lets mktree work on 64-bit :)

-serge